signature-params: Properly handle MGF1 algorithm identifier without p…

…arameters Credit to OSS-Fuzz. Fixes: CVE-2018-6459
strongswan · Feb 19, 2018 · 40da179 · 40da179
1 parent 0bb4d21
commit 40da179
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/src/libstrongswan/credentials/keys/signature_params.c b/src/libstrongswan/credentials/keys/signature_params.c
@@ -280,13 +280,17 @@ bool rsa_pss_params_parse(chunk_t asn1, int level0, rsa_pss_params_t *params)
 			case RSASSA_PSS_PARAMS_MGF_ALG:
 				if (object.len)
 				{
-					chunk_t hash;
+					chunk_t hash = chunk_empty;
 
 					alg = asn1_parse_algorithmIdentifier(object, level, &hash);
 					if (alg != OID_MGF1)
 					{
 						goto end;
 					}
+					if (!hash.len)
+					{
+						goto end;
+					}
 					alg = asn1_parse_algorithmIdentifier(hash, level+1, NULL);
 					params->mgf1_hash = hasher_algorithm_from_oid(alg);
 					if (params->mgf1_hash == HASH_UNKNOWN)